Fully complete dataset export

[bencap]

Although we have namespaces for certain fields and can export most data, certain data does not yet have namespaced fields in our CSV export. We should audit which fields are present in score set display pages (such as ClinVar variants), and add them as namespace options to our CSV exporter. This would allow our exported datasets to contain complete information for all exported information.

[bencap]

As part of this task, we should consider refactoring existing code to make requesting all namespaces simpler and to make our set of available namespaces more accessible to end users.